Grinding machine



Feb 22, 1949. J.' MARTIN GRINDING MACHINE '7 Sheets-Sheet 1 Filed Dec. 15, 1945 lill INVENTOR. 3%5 Mrz,

,f77/MEMS.

Feb. 22, 1949. J. MARTINy 2,462,522

- GRINDING MACHINE FledrDeo. l5, 1945 7- Sheets-Sheet 2 IN VEN TOR.

@i ifm mi Feb. 22, 1949. l.JL MATIN 2,462,522

` GRINDING MACHINE V Filed nec. 15, 1945 Y l 'v sheets-sheet 4 Feb. 22, 1949. J. MARTIN 2,462,522

GRINDING MACHINE Filed Deo. 15, 1,945

' INVENTOR.

GRINDING MAcHiNE Filed Dec. 15, 1945" '7 Sheets-Sheet 6 (5f/2J j l 245) 495 a? INVENTOR.

3207755 )far-fz.

Feb. 22, 1949. J. MARTIN 2,462,522

GRINDING MACHINE Filed Dec. l5, 1945 7 Sheets-Sheet 7 l l 4 l l f o 2.5/ L "z 1 "gil-230! @il a Patented Feb. 212i, 1949 2,462,52gf- GRINDENG .lames Martin, Ferndale, Mich, assigner, ltolviihiy,

gan lTool Company, DtroitQMi'c;

` corpora? Application December15, 1945, SeriaLNo'. 635326755. .6 Siaims. (Cl. 51E-123) .v

This invention relates toggrinding machines.

More particularly, it relates to grinding machine I readilyradaptabie for grindingr the involutensurfaces on flanks of `teeth `of, gear-like` machine elements such as master gears, Shaper cutters, and the like, which may Vary Widely as to size and ,number of teeth.

Asis well recognized, involute surfaces on,

anks ofgear-like machine elements must be precisely and `accurately ground to shape afterk ment.V The problem is further complicated by` the fact that equipment thus usedV is lost for,

some, not inconsideraola time to production.

Obviously, suc-li" practice is not` satisfactory and it therefore, azprimary object of the pres-- ent invention to provide an adaptable and yet at the same time precise, automatic grindingv machine capablev of grinding involute surfaces` on iianks of teeth .of gear-like machine elements which may vary widely in size or in number of teeth'A and which machine requires. no master It is a further object of thepresent inventions to provide a construction by which involute sur-i faces on iianks of dissimilar gear-like machine elements may be groundautomatically and which no way depends upon the skill or ability of an operator to produce work of eXtreme accuracy.

Another object of the present,inventionv is `the provision of apparatus which may bef easily and conveniently adapted to grinding involute surfaces on the flanks of dissimilar gear-like machine eiements. To accomplish this, an sine bar is provided which maybe quickly and easily adjusted to adapt a machine of irlvention for grinding dissimilar gear-like machine.

elements.

Another object of the present invention is the,V

provision of apparatus in which the workpiece is automatically moved as it engages agrinding` Wheel in such manner it progressivelyl contacts the surface of said Wheel along aninvolutepath. Still further, itis an object of the present irl-` Vcntfion to provide, a construction sufcientlyv adjustable Shingle Lin: neatQn :inlays beacon justed by relatively unskilled VbY Si 'lllfuriha theinventio contemplates -provic @Draratusavhch mayrbe. placedfinibat It terr i0 natioaaboutali, 01 er-atm ,tossave valira; ablelooixspace...

Many and furthe/.11i obiectsjadvantasess and. features-,oi the.preseritiinventieniwi lJoes come apparentirom thedescription.Which-,fok; lowsrwhen ensidegedl ,in ,coniunctqn with the .Whiclrlikenume "ais Hed-end ads;

Figure :gli-is` a irontfelevationalr.viewiof fairgrindsing machine embodying the-.improvements ofzzthe present,linientionawith thelaneans lios vertically adjusting; the ,1 grinding wheel showin: partly zinc section for: clarityi,

Figure L2 is a left side:eletationloi.thezgrindings machine ..shown irri-Figuren, partly.` .sectionedito show the adjusting. meansl-of 'the :grindingLhead.'

Figure 3 .is across -sectionediviewltakenonrliriei: oitFigure 2 to more:clearly,,illustrateavarious 'a parts ,ovthelapparatusa Figure 4i is i a `fraumentaryg,...elevational vieum` substantiallyion line fle-l ot Figurel Withavariouspartsaixr sections to'. illustrate im'oreciully and-sh cllearly,v the construction:` and-ii arrangement ofi parts.; i

Figure *5 is, Yai fragmentary,exsectionalfelevation taken'orriineB-lot Figurelfll showing the grinds` 1 ing head.

Figure Vt. is assectional. view.. on", line 1:662.'-0f FigureLlshoWing alportion oilthe rgrinding Wheel` andiapparatusrfor.truingrthe same.4

Figurel 7 Sissa. diagrammatic sketch `of la: fluid: operated@ system .which f may be usedu withx the construction .disclosed by the present invent'ion;`

` Figure S8l is a :section- .taken Yon .linefS-l-'Siof Eigure, showing ,the fluid responsive piston andeV cylinder for moving the workpiece, .one 'connection of'xwhichis displacedQO deg-rees forsclarityi.

Figure 9 is a fragmentary, elevational;y View,1 takenin. the directionbf arrow/H9, Figure .if with covering omitted,4 showing;` the :indexingemecha anisrri.

Eigure, .11; is anfenlargedf-section ztaken'. sub` stantially on line H-II of Figure ,9.f`.

According; tothe present invention; .aconstruction isprovided in which-,arworkpie'ce islpositiorrediz bymea-ns of a work holder so` the involu'te surfaces-. thereoipmay be vengagedirr proper scyzquence byf asurfaceof a rotatingggrinding Wheel, saidsurface J beinslnormal-to'the axisbfsroiaticnrofrsaid Wheels;

The work holder provides for moving the Workpiece as it engages the surface of the grinding wheel in such manner it progressively contacts said surface along an involute path. An automatically actuated index mechanism presents each tooth to the grinding wheel until the operation is complete, at which time the grinding Inachine automatically ceases operating until restarted by the operator.

Provision is made by means of the work holder for accommodating a helical workpiece with angularly disposed flanks and also for accommodating a workpiece having flanks of considerable length, that is to say a workpiece having a wide face.

The drawings disclose but a single embodiment of the grinding machine of my invention, which will hereinafter be described more fully. It will become obvious that many modications thereof and departure therefrom may be made without departing from the spirit or scope of the invention as described and as claimed in the hereinafter appended claims,

For a more detailed description of the invention, reference may be had to the drawings in which a base is generally indicated at I. Such base may be formed from an integral, hollow casting with doors through which access is gained to certain, hereinafter described, portions of the apparatus housed interiorly of said base.

In order to accomplish the grinding of a workpiece, a grinding head generally indicated at 2 is mounted on an upwardly directed portion of said base by means of T-bolts 3 which engage T-slots 4, 5 of slide plate 6.

Such plate E is received by machined surface and slideway 8 of base I for sliding movement thereon and provides for adjustment of the grinding head to bring the grinding wheel into contact with the workpiece and arcuate adjustment of said grinding head to angularly position the grinding wheel to the pressure angle of the teeth of the workpiece in a manner to be later described.

Said grinding head provides for a generally circular, abrasive grinding wheel 9 which has surface .I normal to its axis of rotation. This grinding Wheelis mounted on a spindle I I for rotation therewith by means of collar I2, thrust washer I3, and nut I4 threadably engaging said collar at I5. This combination is secured to said spindle by nut I threadably engaging said collar and spindle at I,. I8, respectively.

Spindle I I is journaled for rotation in bushing I9 and thrust bearings 2), 2l o-f annular sleeve 22. The annular sleeve 22 is received in hollowannular support 23 which extends downwardly from slidable mount 2li. Bolt 25 secures said sleeve 22 to said support 23. A nut 25 is provided to threadably engage spindle II at 2l and presses against bearing 25 to prevent side play of the spindle. Cap 28 is secured to sleeve 22 by bolt 29 to prevent foreign matter from entering the thrust bearings.

Said grinding head provides for driving grinding wheel 9 by means of a suitable electric motor 39. Motor 39 is secured to mounting plate 3i of said grinding head at an outwardly projecting portion 32 thereof. T-bolts 33 engage T-slots 34, 35 in said projecting portion to rigidly secure said motor thereto.

This driving is accomplished by energizing motor 39 to drive motor shaft 3S and pulley 3l. Pulley 3l' drives a continuous belt 38 to drive pulley 39 keyed at 49 to spindle shaft I I, rotating the same. It Will be obvious that pulleys 31 and 39 may be chosen of suitable ratios to give the speed desired to the grinding wheel. It will be observed, too, that adjustment is provided to obtain proper belt tension by shifting the position ci motor 30. This is easily accomplished upon loosening T-bolts 33, permitting them to slide in T-slots 34, 35. Said motor may then be relocated to give the desired tension in the belt, and the bolts tightened.

It is pointed out that the grinding wheel driving means is independent of other driving means and motor 3l) is independently controlled by start and stop buttons 4I, 42, respectively, which control the supply of electric current to said motor 30.

To accomplish the extreme accuracy required in a grinding operation of this nature, it is necessary to dress the grinding wheel at intervals. Therefore, a means for dressing the grinding wheel is also provided on the grinding head.

The dressing of grinding wheel 9 is accomplished by means of dresser 43 mounted on outwardly extending ear 44 of the mounting plate 3I. This dresser is thus mounted at the longitudinal axis of spindle I I and is normal thereto. Said dresser is provided with a diamond-pointed tool 45 (Figure 6) at the end of rack 45. Rack 46 engages threaded portion 4l of feed screw 48 which is rotatably mounted in a suitable bearing at 49. t will be observed that as feed screw 48 is rotated by means of handwheel 59, rack 45 will advance tool i5 toward the periphery of the rinding wheel.

As a further aid in the dressing operation, previously described, slidable mount 24, carrying spindle II with grinding wheel 9, may then be moved laterally inwardly toward tool 45.

r'his slidable mount depends by means of slideway 5I from outwardly projecting portion 32 of mounting plate 3| with said slideway 5I and machined surface 52 of projection 32 providing for the sliding of said mount.

The sliding movement by Which grinding wheel 9 is laterally moved is accomplished by means of -feed screw 53 journaled for rotation in a suitable downwardly directed bearing plate 54 secured to outwardly projecting portion 32 by screw 55. The threaded portion 55 of said feedscrew engages lead nut 5l anchored to slidable mount 24 by screws 58. A handwheel 59 is integrally connected with the feed screw and it will be observed, as said handwheel is rotated, slidable mount 24 may be slidably moved as described.

When the dressing operation is complete, grinding wheel 9 is returned by means of handwheel 59 to operative position and diamond tool 45 is retracted by means of handwheel 50.

It is pointed out that adjustment of the grinding wheel by means ofl handwheel 59 is only for use in the dressing operation. It is not intended to be used to adjust the grinding wheel during the grinding operation.

As hereinbefore stated, slide plate 5 provides for adjusting the grinding head to bring the grinding wheel into contact with the workpiece and angularly positioning the grinding wheel at the pressure angle of the teeth of the workpiece,

This adjustment is accomplished by means of feed screw 60 journaled for rotation in suitable bearing 5I of a gear housing 52. Such housing 62 is rigidly anchored at the top of the upwardly directed portion of base I. Feed screw 60 is threadably received by lead nut 63 anchored to slide plate 6 by bolts 64. A bevel gear 65 at the upper extremity of said feed screw meshes another bevel gear 66 on rotatable shaft 61. Said shaft 5l is journaled for rotation, perpendicular to feed in hearingportionof the gear housing `conveniently.:accessible handwheel 59 .is Rmvided,toirotate:shaft-167, and it is JClear from th eseribed-constructiomthat rotation there-of gli servetoiverticallyrshift said slide plate t and the grinding-head thereon.

In order that the grinding Wheel may he locked inlporsitiontwhen this adjustment is accomplished, a, locknut liiwith handle l! isrprovided. Such lock nut serveslto positively anchor the slide plate, andl thus the grinding wheel in adjusted position. ,Arcuate `adjustment', of the grinding head to angularly position the grinding Wheel at the pressure angleof thevteeth on the workpiece is accomplished by means of the arcuately disposed 'l'.rslotsll,v 5, in slide plate E. Such slots permit grinding head2 to be moved arcuately as T-bolts 3 are loosened to move slidably in said slots.

'.'lhismovernent of the grinding head is acculately-.controlled by feed screw 72 journaled for rotation vinoutwardly directed bearing "i3, which is, mounted onupwardly directed portion of base |"for.rotation perpendicular to that of the feed screw. This feed screw is threadably received by leadnut 14, which is mounted on mounting base 32 for rotation perpendicular to that of the feed SGILSW. The` feed screw includes an integrally con nectedhandwheel'l, Awhich when rotated, causes thefbodily shifting of the grinding head to position grinding wheel 9 accurately at a predetermined pressure angle. The bodily shifting of the grinding head as thefeed screw is rotated necessitateshaving bearing 13 and lead nut M rotatable, asitwill be observed that the feed screw will move arcuately'as lead nut `I4 travels on said feed screw. Suitable graduations are provided at it and l'i to measure angular displacement of the grinding wheel, thus permitting'extremely accurate control over the adjustment thereof.

lIt :will be clear that aiterrthe grinding'wheel is adjusted toa predetermined pressure angle in the describedimanner, T-bolts 3 may be tightened in T-slots 4, 5, to lock the-grinding head and thus the grinding wheelrigidly and securely in position.

`:Inorderuto support workpiece `i8 during the grindingoperation, a work holder, which is generallyV indicated at 19, is mounted on hase i below grinding .head 2. This work holder is an integrated. vunit which coordinates the function of its components tol accomplish the grinding of gearlike.-v machine elements in a manner to be herein-- after described.

\-,\Broadly thework holder comprises a compound carriagey, upon which are mounted work head 8 land tailstock 82.

Thejcornpound carriage, generally indicated at 80, consists of a ylower reciprocable ,table 83, a middle adjusting tableli, a swivel 85, `and an upperreciprooable table B6.

The lower reciprocable table 83 is provided to accomplish reciprocation of the work holder par allel to the pitch line of a ank of a tooth of the workpiece or movement which may be resolved into such reciprocation when grinding gear-like niachine elements having wide faces; that is to say, those having flanks of considerable length. Means are provided,v however, to prevent this reciproationif the workpiece has a narrow face. 1in-this eventi table 83 may be, if desired, used as a manually operated adjusting table for placing thepworkpiece `in predetermined, longitudinal locatiortmith respect'to the grinding Wheel .and locked thereat.

guchttableds.-.slidably .-mounted upon slideway 8l. and. machined isurface':y 88..1of basezll i morder to ...accomplish reciprocationxithereof, .flsuit'able driving meansiaredioused interio'rlyioffrbasevm l" to be driven by motor 89 mounted thereineatsllll.

This. motor ,is controlled initially ,byyaumanually operable,l selectorfswitchy notzshown. -iz'Ilfleasuppl-y of u electric g current, to said switch..is;controlledgby start andfstop buttonst MiB-2, irdspectively, which ara-provided for main fdrivezfzmotor .S3-asi flirte later described. -lhusnaitelnthe .selecto switch is closed to supply electriccurrent;to.=;saidsmotor, this motor ,may .bat-hen tontrolledfihr; means, of saidvstart, stop buttons.

Upon initiating operationoofigmotor 189 said motor-drives motor shaft 96 and,aclutch 95 keyed theretoat. -This clutch iinit @i able clutchY unit 99 mountedto` slide iupon shaft it which itjdrives byl means of `keyiltll.` s

pointed out that the clutch unitsfare sho engaged (Figure 3)` for clarity'. It W' that saidunits lmust be engaged whenlreci s tion is to beraccomplished bynieans of.. no 1',`,

Such shaft la is journaled forrotatidri in ings ft2, 103, providedby ribs .T04 i'llhlof connected to shaft lililgbymeanslofjkeyd, nut i i, is driven by said shaft. Gearf l IZmeshes gear iiE, which gear U5 is integrally V` coniiected to shaftildby means ofkev` Illl andput ,M8 which threadably engagessaid, shaft', landdrives the same. Shaft il'isgjournaledgfor rotationtin bearings H9, l of previously described ribs IGIL m5 and is prevented from`gmoving"1ongitudinaily by means ofthrust washers I'ZLV'EZZandfthriist collars 423, 24 pinned thereto atl25, 126.; fSaid shaftv H6 drives geariN pinnedtheretoat"i128, which gear nieshesgear E29 keyedatiffil'ftofdiive feed screw i3! for drivingtable."

Such feed screw i3! is journaled'l-forf rotation in bearing |32 providedbybase"Igand-beaingi anchored to project outwardly from "said base. This feed screw is threadably-receivedTbyia lead nut |34 anchored to dependvfrorn table-'83. It is clear from the description that table 83=-vvi l. shifted as the 4feed screw rotates to-acc the bodily shiftingof the work hinder.'

Automatic reciprocation is provided by -nieans of i limit switch 35 t which'reverse's the Yrotation of motor 89. Dogs 135,431, dependingbylmeans-of T-bolts I 38 from lrecip'rocable table 83, farepositioned to l contactswitcharm: liit--ofsaid `switch. Such dogs maybe shifted -by?slida'bly mov-ing T-bolts Ai356 in 'af-slotf-li49 to terminall-yf-l'iniit' the travel of `table 83 -to the length oflthe toothiia'nk. As each dog reaches its-respective limitfi iontacts i said switch arm 39 effectingL reversal i' Aof the rotationof motor-89; changingthe direction ofreciprocation of `table 83.

It is` to be observed that thisv reciprocation'lis not always parallelto. thefpitch'linel of ailfiank of the workpiece. This reciprocation'is aloiig}an axis of the grindingmachine;-f-When`-\the wrkpiece has ang-ularlydisposed flanks, as-is`the case` with a helical gears-thisreciprocationis `'resolved into reciprocation parallel t the-pi "h line of aiiank tooth by means of swivel 1` ner to be explained as said swivel? and its unc-- tion are described.

t Control" over theV speed ofreciprocation is provided bymeans-of lchange 4gearsvl lf2r`,ffi l5. Said gears become -accessiblefupon removaloftdbrf-H l covering opening |42 provided in bas The gears may then be replaced by others having a ratio suitable to produce the desired speed of reciprocation.

As previously stated, it is sometimes desirable to prevent reciprocation of table 83 and use it for adjustment only. In this event, the selector switch controlling motor 69 is left open and said motor is idle. When such is the case, the jaws of clutch units 95, 98 are disengaged to permit man-- ual operation of the feed screw |3| This is accomplished in the following manner. A spline shaft |43 is mounted for rotation in bearings |44, |45 provided by bosses projecting from the walls of base l. Such shaft engages the annular teeth-like grooves of slidable clutch unit 98. It will be observed that rotation of shaft |43 will accomplish the slidable shifting of said unit upon shaft and disengagement of said units will result if shaft |43 is rotated in a direction away from clutch unit 95. This will leave feed screw I3! and the driving means thereof free to be rotated by a conveniently accessible handwheel |46. Said handwheel may then be slidably moved inwardly on feed screw |3| to effect engagement of jaws |41, |48 of clutch units |49, |50, respectively. It will be clear that thus engaged, these units will cause rotation of the feed screw as the handwheel is manually turned, inasmuch as unit |49 is integrally connected to said handwheel and unit |50 is pinned at |5| to the feed screw |3|. It will be observed that the shifting of table 33 will then be accomplished as the handwheel is turned in a manner similar to that previously described for reciprocation thereof.

In order that table 83 may be, when manually adjusted, locked in predetermined, adjusted position if desired, a lock nut |52 is provided. By means of handle |53 attached thereto, it is possible to tighten said nut and positively anchor saidv table in predetermined, adjusted longitudinal position with respect to the grinding wheel.

VVIn order to position the workpiece laterally with respect Yto the grinding wheel, work holder 80 provides what I have chosen to call a middle adjusting table 84. This table is slidably mounted upon surface |54 and slideway |55 on top of table 83 to move in a direction perpendicular to the direction of reciprocation of said table 83. As in the case of table 83, swivel 85 must be used in conjunction with this table when the ank of a tooth of the workpiece, as for example a helical gear, is angularly disposed with respect r to its axis of rotation in order to resolve the shifting movement into movement normal to the pitch line of the tooth ank. When, however, the workpiece is, for example, a spur gear or its equivalent, it is equally obvious that swivel 85 need not be used, inasmuch as the flank of a tooth on such type workpiece is not angularly disposed with respect to said axis. In this case, shifting of table 34 accomplishes the desired result directly.

This slidable shifting of table 64 to laterally position the work holder, and thus the workpiece, is accomplished by means of feed screw |56. Said feed screw is j'ournaled for rotation in suitable bearings |51, |58 provided by gear housing |59 anchored to table 84, at Vone eX- tremity thereof. Said feed screw threadably engages lead nut |60 anchored to depend from said table. A gear |6| is pinned at |62 to said feed screw to mesh gear |63 pinned at |64 to shaft |65.

This shaft |65 is rotatably supported by bearings |66, |61 of said gear box and has a handwheel |68. It will be clear from the description that rotation of the handwheel imparts rotation to the' feed screw by means of the gears to shift the tab-1e for laterally adjusting the position of the work holder.

In order to lock the work holder in predetermined lateral adjustment, if desired, a lock nut i 69 is provided. This lock nut may be tightened by means of handle |10 to positively and rigidly anchor table 84 in predetermined lateral adjustment with respect to the grinding wheel.

As stated herein previously, in connection with the description of tables 53 and 64, provision is made in the work holder to accommodate a workpiece, such as a helical gear, having the flanks of the teeth angularly disposed with respect to the axis of rotation. Adjustment for this condition is provided by means of swivel 85 of said work holder. Such swivel 85 is rotatably mounted upon machined surface |1| of table 84 by means of pivot pin |12 to rotate in a plane parallel to the axis of rotation of the workpiece.

Rotation thereof is accomplished as a worm |13 is rotated to travel on worm gear |14. Said worm is supported for rotation in suitable bearings (not shown) in a downwardly directed side of said swivel. Within the interior of said swivel 85, worm gear |14 is concentrically mounted with respect thereto by means of the pivot pin |12.Y Hub |15 of said gear is anchored to table 84 by bolt |16, preventing rotation thereof. This hub is of sufficient height to line up the gear with the worm. The pinion shaft |11 is provided with squared end |18 to which a crank or other suitable means may be applied to rotate said pini-on. As said worm |13 is thus rotated, it moves swivel 85 around the stationary gear |14 by means of shoulder |19 on shaft |11 which bears upon the side of the swivel. In this manner, a ank of a tooth of the workpiece may be placed parallel to the plane of rotation of the grinding wheel.

It is this rotational adjustment which resolves the reciprocation of table 53 into reciprocation parallel to the pitch line of a flank of a tooth of the workpiece and resolves the lateral adjustment provided by table 84 into movement normal to said pitch line when said flank is angularly disposed with respect to the axis of rotation of the workpiece.

When this rotational adjustment is accomplished, swivel 85 may be locked in predetermined angular position by means of T-bolt |86 which moves slidably in the circular T-slot |8| provided by table 94. Swivel 85 has a depressed portion |82 in its downwardly directed side by which access may be obtained to a nut |03. Said nut 83 threadably engages T-bolt |30 and provides for tightening said bolt in T-slot |8| rigidly locking the swivel in adjusted poston.

The angular setting of the swivel is conrotation during the grinding operation. This' reciprocation is provided by' upper reciprocating 9 tablefg., The 'work rhead Slis -integrally a part oil-table 86 land ,tailstock 82 is Iadjustably mounted thereon by means of T-bolt |83 mounted to slide irl- T-Slot |8?, Inasmuchas tailstockY 82 is conventional `and'gis' ,not claimed as part ofY this invention.; it .is not furtherv described.

Table 83 is mounted on balls E33 inrac ways |80, |90,V |0| toireciprocateupon swivel 85. It Willi-be. observedthat this table, and hence the work head andtailstock are rotatable to angular position by means of the swivel.

Reciprocation of the workpiece by means of table 86 is effected asa-slide block |92, operativelyfassociated with a fluid responsive cylinder |53,

reciprocating perpendicularly to the plane of reciprocation'of said table, is propelled by such cylinder in such manner it is slidably moved along asloping. sine bar |94;

Thesliding movement ofthe slide block i92, resulting in reciprocation of table 86, is brought about in the following manner. Work head ai, previously noted-'as being integral with reciprocating'table .83, provides machined surface |05 and slideway |98 toslidably receive side le? of reciprocating cylinder |93. At the upper extremity offsaid machined surface |95 and slideway |93, ther,wruk-,head provides `an outwardly projecting arm having opening |981therethrough through which piston rod- |559] ispermitted to extend. Such piston rodis^ rigidly -secured therein by bolt 200 and` held ingits stationary position as said cylinder reciprocates. An outwardly directed projection ofcylinder |03 forms ear 20| which provides a suitable opening through which pin 20,21 ofvslidev block |92l is permitted to extend. Thus, as fluid is-admitted at alternate intervals tofchambers 203,' Zilllgiligure 8) on opposite sides, respectively,v oipiston 205l in said cylinder |93, such cylinder reciprocates, and it is evident that slide block |32 will tend to move with said cylinder. However, this slide block is constrained by groovev 203' of` sloping sine bar I-Qi'and'can only slidestherein. It will be apparent that as slide block- |92` slides in groove 206, it travels laterally with respect to the grinding wheel. lateral movement of the slide block which shifts table 86 andworkpiece 18: therewith.

In order to leciprocate table 86 automatically, pilot valve 2011s providedI to effect the directing of pressurizedfluidalternately to chambers 2i33, 204Iof'the'cylinder |93: This valve 20? is provided Witharms 208', 29to be contacted by dogs 2 l0, 21|, mounted on saidcylinder |03, as each in turn reaches its terminal limit. Upon contact, said valve arms 20.3, 200 cause the shifting of a .iston (not shown) in a-four-way valve 2| Z'to direct the pressurized fluid to opposite sides of piston 205.

TheV grooved sine bar |341 controls the reciproeatingv movement of table 86. This sine bar is mountedon an outwardly extending arm of previously described table 35 for arcuate adjustment into a sloping position. -bolts 213 slidable in arcuate T-slot 2 it', in said extending arm, provide means for rigidly locking. the sine bar in predetermined sloping position. This slope may be accurately controlled by suitable means such as gage blocks which may be placed between polishedsurface 2.15 on said extending arm and measuring pin 2 3 on said sine bar. It will be observed that sine ba-r |34 must be angularly adjustable to the angular position of table 86 in order toA maintain slide block |92l in groove 203. 'Ehswas accomplished by mounting the sine Vbar onzen, extension ofjfthe, swivel'S-Li.

Control: ofg'the recprocator-y movement or: table It is this ILT:

86 by means of sine bar lgisaccomplished by changing the slope of the same. This desirable result is utilized to eliminate the necessity of using a master roll on a grinding machine of my invention. It is this simple expedient which permits a grinding machine ci my invention to be easily and quickly adapted to grinding gear-like machine elements which vary widely in size and number of teeth.

During the grinding operation, workpiece 18 is rotatably support-ed between, spindle 2|? of work head 8| and center 2|8 of tailstock-` 82 by suitable means for rotation by said spindle.

For the purpose of .grinding a ilank on a tooth of the workpiece, said workpiece is partially rotated in an oscillatory manner about its axis of rotation. For indexing, the workpiece is inter. mittently rotated until all the teeth thereon have been presented to the grinding wheel. Work head 8l provides separate means by which` this partial and intermittent rotation is separately imparted to said workpiece.

In order to provide for the partial and indexing rotation of workpiece TF3, spindle 2 I? is journaled in compound bearings 2|9, 220, 22|, provided by said work head 8|, and a sleeve 222, for rotation Within said sleeve. Such spindle 2|? is held therein by nuts 223, 224 which threadably engage said spindle and prevent longitudinal axial movement thereof.

Various interconnected, mutually operable, units are provided by the work head 8| to accomplish the partial rotation of workpiece 18 by means of spindle 2|?.

Sleeve 222 in which spindle 2|? rotates is journaled for independent rotation in compound bearings 225, 225 and upon the outer races of compound bearings 220, 22|. This sleeve isY integrally connected by bolt 22? to rotatable disc 228 and provides for rotatably supporting said disc.

Such disc 228 has iiexible bands 229, 230 secured in grooves at the top `center thereof by tabs 23S, 532 and flexible band 233 secured in a groove at the bottom center thereof by tab 234. It is to be noted that the combined width of upper bands 229, 233 equals the width of lower 233. in this way, the tension exertedl by the bands on. disc 228 isequalized. The opposite ends or said bands 223, 23! are secured to the bottom of reciprocating cylinder |931 by clip 235 and thus connected, are partially wound on the p phery of disc 228. The opposite end of band secured to the top of said reciprocating cylinder les by tab 2,35 and this is partiauy woimd on the periphery of disc 222 between 229, 230. in order to adjust the length of the bands, clip 23E provides for the samewith an adjusting bolt at 23?. By means of this adjustment, bands 22S, 235e may be lengthened or shortened, automatically adiusting band 233. It will be clear from the description that as cylinder 93 reciprocates, the bands will cause to rotate in an oscillatory manner as they alternately wind and unwindon disc 228.

This rotative movement is transferred to a Worm gear 235 integrally connected to disc 228 to a built-up support 230 anchored to face pia-te 24? of said gear. Support 239 carries therein a push pin 212|, which pin has at its upper extremity a lip 242 in which a groove 243 provided Within this groove. an index 1inger 2636i is` held by pin toextend downwardly parallel to the longitudinal axis or push pin 241;; The front face. off support 239-providesnl1f@19n- 11 gated opening 2:36 through which a pin 261, securedjto index nger 244, is permitted to pass. This pin prevents sidewise movement of said index linger.y

V4The index nger, thus held, is disposed between the lperipheral serrations 248 of an index plate 249 integrally connected to an extremity of spindle 2|1 by means of nut 250. In this manner, the rotative movement of disc 223 is imparted to'the index plate and thence to the spindle-211 and workpiece 18.

y It is this partial rotation of the workpiece which combined with the reciprccatory movement provided to said workpiece by table 86 effects alank of a tooth thereon to progressively contact the surface I of the grinding wheel along an involute path.

It is a fact, recognized by those skilled in the art, that a machine element, such as a gear, having involute teeth will roll in a rack having straight teeth. In a grinding machine of my invention this principle is utilized. The straight surface 'i0 of the grinding wheel can be considered one side of a tooth of an imaginary rack. The combined rotative and reciprocatory movements given the workpiece produce a resultant rollingmovement effecting a flank of a tooth on said workpiece to roll into and out of engage ment with'said surface of the grinding wheel in a manner similar to that of a gear tooth on a reciprocating gear rolling into and out of engagement with a rack tooth. It is apparent that the'linear movement, as measured at the axis of rotation of a gear thus rolled, is af fected by the size of the gear or number of teeth thereon in order for a tooth thereof to roll out of engagement with the rack. In production equipment, a different master rollror master gear is provided `for each different gear to properly move a workpiece thereon. A machine of my invention, as stated previously, requires neither a master roll nor master gear to supply the proper linear movement to the workpiece during the grinding operation. The previously described adjustable sine bar controls, with extreme accuracy, the reciprocation of table 86 to provide the required linear movement for any workpiece regardless of size or number of teeth thereon. It will be evident, too, that said sine bar may be readily and quickly adjusted by comparatively unskilled labor to adapt a grinding machine of my invention for grinding gear-like machine elements which yary widely in size and number of teeth. Thus, by utilizing a wellknown principle, I have invented a new and novel method of providing the required linear movement to a workpiece whereby a single grinding machine may be easily adapted for grinding gear-like machine elements varying widely in size and number of teeth without using a master roll or master gear.

The indexing rotation provided by work head spindle 2|1 to present each tooth of the workpiece to the grinding wheel is accomplished after table 86, of which said work head is an integral part, is reciprocated a definite number of times by means of cylinder |93.

As said cylinder |93 reciprocates, lower runner 25|, and upper runner 252 thereon slidably contact limit switches 253, 254, respectively. Upon'contact, said switches complete electrical circuits to a counting device (not shown) for counting the number of reciprocations. This device may be adjusted to permit cylinder |93 andtable 86 to reciprocate', in accordance'with the be observed that as'rack 260 'reciprocates inwill of the operator, a predetermined number of times to permit the tooth being ground to acquire a fine nish.

When the desired number of reciprocations have been made, various mutually operative units effect indexing rotation of spindle 251 and thus, workpiece 18.

At this instant, the counting device closes another electrical circuit, energizing solenoid valve 255. This valve then permits pressurized fluid to enter chamber 256 of cylinder 251 anchored to the work head. As fluid enters this chamber, fluid responsive piston 258 and piston rod 259, to which rack 29) is integrally connected, reciprocate inwardly.

Such rack 26E is provided to simultaneously rotate gear 26| slidably mounted upon bushing 262 on sleeve 222, and to oscillate a shifter 263 for slidably moving said gear toward surface 265 of index plate 229. This movement of shifter 263 causes contact pins 265 thereon to press upon surface 269 of gear 26| for effecting sliding movement of said gear toward surface 264 of index plate 249. This sliding movement of gear 26| increases the pressure between friction buttons 261, carried by gear 26|, and surface 251i of index plate 249 to accomplish rotation of said plate by means of said gear.

In order to os-cillate shifter 253, rack 269 is thin at one extremity and sloped at 268 to a greater thickness. As said rack reciprocates inwardly, the head of a bolt 269, passing through the shank of shifter 262 to contact said rack, effects said shifter to move in an oscillatory manner about pin 21d because of this variation in thickness of rack 269. Such pin 219 extends through mating openings in said shifter shank and supports 21|, 212 provided to slidably support rack 266 upon machined surfaces 213 thereof.

The friction buttons 261, by which gear 26| rotates index plate 229, are carried within blocked openings 214 of gear 26|. Compression springs 215 are disposed within cavities 216 of said friction buttons and bear upon the lower surface of openings 219. A neck portion 211 of said friction button protrudes through a'clrilled opening in shoulder nut 218 which threadably engages a tapped portion of blocked opening 214. It will be observed that as said nut is tightened, it bears upon shoulder 219 of friction button 261, compressing spring 215 to yieldingly mount said friction button in said opening 214. Thus, as gear 26| slidably moves toward surface 26d of index plate 2139, it will be evident that the pressure between said friction buttons 291 and surface 264 will be increased as springs 215 are further compressed. This increased pressure produces suffi-cient friction between said buttons and said surface to effect the rotation of index plate 249 with gear 26|.

Before it is possible for this indexing rotation of index plate 249 to takev place, however, index nger 244 must be removed from the serration of said index plate in which it is currently disposed. This disengaging action is accomplished bythe combined action of a cam 289, anchored to rotate with gear 26|, and cam follower 28E, depending from push pin 24|.

Such cam follower depends'from push pin 24| by means of pivot pin 282 and is continuously caused to contact the surface of cam 28a due to the action of compression spring l283 disposed at the opposite extremity of push pin 24|. It will andasself3 wardly, gear 251 will rotate cam 28@ to .move follower Z3! and .push pin 2M; simultaneously effecting further compression of spring 283 and removing index finger 25.5 from its locking position in a serration of said index plate.

The index linger is held in such disengaged position only for a time sufcient to allow index p11-ate 249' tc begin the indexing rotation. At that instant, cam follower @Eli passes over the crest of cam and compression spring 2&3, actingv on push pin Edi, forces index finger Zifi into Contact with the peripheral edge of index plate 269. This permits said index finger to follow said peripheral edge to the immediately succeeding serration in said periphery, into which said index finger is forcibly disposed by the action of such compression spring, thereby locking the index plate against further rotative movement.

It will be quite obvious that the number of serrations on index pl ic 2li!! must be equal to the number of interde: -al spaces between the teeth of the workpiece. This has been provided for by making said index plate removable when necessary. It is quite obviously seen that the index plate may quickly be changed by removing nut 250, after which said plate may be removed and replaced with another having the desired number of serrations.

After this indexing reciprocation of rack Zeil, limit switch 254 effects the return of rack 26S to initial position. At the termination of the inward reciprocation, rack 25o contacts arm 285 of said limit switch. This again energizes solenoid valve 2te, causing said valve to reverse the flow of pressurized fluid from chamber 25S of cylinder 25'! into chamber 28e thereof, reversing thereby the direction of reciprocation of the rack.

Reciprocation of rack 2Gb in this outward direction rotates gear 25E only, inasmuch as index plate 249 is locked by index nger 22M. In providing for such rotation, cam follower 284 was constructed to pivot about pivot pin 282, to prevent lifting of index linger during this reverse rotation of said gear. It is to be noted that surface 28l of said follower a portion of a circle and, as cam 28e is reversibly rotated, permits the follower to pivot the cam moves. In contrast, surface 233 thereof is nat to bear against the adjacent flat surface of push pin 2M, preventing said follower from pivoting during indexing rotation of the cam. When cam 288 returns to its initial position, tension spring ESQ, secured to eye 29123 of said follower and to disc 228 by pin Eel, forcibly pulls the follower into position for the next indexing action.

Reciprocation of rack 25E! in this return direction also relieves the pressure between friction buttonsv Ztl and surface all cf index plate 24S. It will be seen that as rack 26% reciprocates to an initial. position, the head of bolt 269 will again contact said rack at its thin extremity and shifter 263, due to its eccentricity with respect to pin Zlfl., will oscillate to its initial position. This eliminates the pressure between Contact pins 265 and' surface 2&6 of gear 26| which in turn relieves the pressure between said friction pins and the index plate surface.

As theteethof the -e-forkpiece are' in this maniner presented to the grinding wheel, a second counting means (not shown) is provided to coun-t the inward reciprocations of rack 26d. This counter is adjustable tothe number of teeth on the workpiece andi is alsov activated by limit switch 28e` asl rack' 26d contacts arm 285 ther'eo'fl a graduatd 11'4 Inasmuch a'ssra'ck 2te makes one such reciproca'- tion for each tooth, this affords a simple means to insure thatv all teeth are presented to the workpiece.

After all teeth of the workpiece have been preto the grinding wheel in this described manner, it is at times desirable to remove an extremely small amount of stock. Provision is made to rotate previouslyT described gear 26T to accomplish a fine adjustment of the workpiece such operation.

efore this fine adjustment may be made, it is necessary to unlock gear Stil from disc 228. This effected by loosening bolt 292 which passes arcuate opening E93 in said gear to i rotation. It will 'oe apparent that gear 261 must Sie locked again alter the adjustment is made in order that rotation of disc 223 be imparted to gear and 'thence to index finger 2M.

In order to accomplish this adjustment, a

z manually rotatable shaft 2525, having worm 296 formed thereon, journaled for rotation in an provided by disc 228 by means of bearings illl. means of knob integrally attached thereto, worm drives crm gear till and shaft 302 for "ing worm formed on said shaft. Such ft 352 is rotatable normal to shaft 28-5 and is osed within an opening 35i of disc 228. Said provi .es bearing surfaces 305, 3% to bear .st the wall of opening Se@ and also provides an annular groove Se? to receive pin 398 which is secured to '328 to prevent the lower face of worm binding on the bottom surface of opening Thus, as worm 3523 is rotated, worm gear 257 rotates, effecting index linger 2M to press upon the side of the Serrat-ion of index plate 249 in which index linger is currently disposed. This causes index plate M9 to rotate workpiece lil toward the grinding wheel in readiness for grinding.

As a

s for controlling this ne adjustment, wheel fille is secured to shaft Een. enables the operator to control the necessary adjustment with extreme accuracy as he incr-Jes the wheel past the indicator mark at 3 l D.

It is pointed out that this adjustment is limited to the length. of arcuate opening Zet in gear 261 which is only one and one-half times the diameter of bolt Such adjustment is intended to augment the previously described adjustments when an extremely small amount of stock is to be removed from a ank of a tooth.

Up to this point nothing has been said about a means for driv' this grinding machine. In order to drive a grinding machine of my invention, driving means are provided interiorly of base I'. e suitable prime mover in the form of an electric i iter is provided to drive double pump 3H. Electric current may be supplied to said motor from a convenient source, the supply being corrtrol: d' by start button .fil and stop button 92.

Such pump Eil supplies fluid under pressure through line 3 i 2 to port 353 or four-way valve 314. Said valve. in this system, has two ports plugged is to close the circuit or permit all the fluid to pass through port SI5 and line SIS for return to reservoir l'l which stops the machine without stopping motor de. rThis is a solenoid valve which may bei operated manually to initiate operation ofthegrindingA` machine, andoperatedE As such shaft is rotated byl by means of the solenoid to automatically stop the same after the grinding operation is completed.

YI'oeifect the closing of port 315 in valve 314, control lever 318 (Figure 1) is manually moved. Pressurized fluid then travels through line Slg to port 323 of solenoid Valve 255; through line 321 to port 322 of four-way valve 212; and through line 323 to port 324 of sequence valve 325.

Such valve 212 is controlled by means of pilot In this system, one port of said valve is plugged, and depending upon the direction of reciprocation of cylinder l93, port 326 is alternately open to pressure port 322 or reservoir port 321.

The automatic reciprocation of cylinder 193 is accomplished by pilot valve 231 as previously described in connection with reciprocating table 86. Fluid under pressure is delivered by line 328 to port 329 of this valve. In Figure 7, said pilot valve is shown with port 3311 and line 331 open to port 329 with port 332 closed. This effects valve 212 to open port 323 to port 322 and closes said port 326 to port 321, permitting delivery of iiuid under pressure to line 333 and passageway 334 into chamber 203 of cylinder 193, reciprocating said cylinder downwardly. Simultaneously pressurized iiuid'from chamber 2134 is exhausted by way of passageway 335 and line 335 to port 331 of valve 325 for return therethrough to the system. This is known as a differential system and cylinder 193 is termed a differential cylinder. In

v order for such system to function, the ratio of surface areas of lpiston 235 must be 2 to 1. In this invention, the lower surface 338 of said piston has twice the area of upper surface 333 to piston rod 199 being sufficiently large to make this ratio possible. It will be evident that such system permits cylinder 193 to reciprocate with equal speed in either direction.

When pilot valve 201 is shifted to an alternate position by dog 2139, port 332 and line 340 are open to port 329 and port 331i is closed thereto. This effects valve 212 to open port 326 to port 321 and close said port 325 to port 322. In this condition, fluid under pressure ows through line 323 valve 325, line 335 and passageway 335 into chamber 204,'reciprocating cylinder 193 in an upward direction. At-the same time, uid in chamber 203 is exhausted by retracing the path to port 326 for delivery to port 321 and to reservoir 311 by way of lines 341,342,316.

' In connection with the description of the indexing mechanism, it was explained that the indexing reciprocation of rack 253 took place after a predetermined number of reciprocations of cylinder 193. For this indexing reciprocation, solenoid valve 255 opens port 320 to port 343 and line 344 to chamber 255. Simultaneously, port 345 is closed to port 320 and opened to port 346 to allow fluid in chamber 286 of said cylinder 251 to exhaust through line 341 for return by way of said ports 345, 346, and lines 342, 316 to reservoir 311.V Reciprocation in an opposite direction to return rack 263 to an initial position is accomplished when this circuit is reversed as limit switch 234 actuates solenoid valve 255 to open port 345 and line 341 to chamber 235. At this time, port 343 is closed to port 325 and open to port 345 to permit fluid in chamber 255 to exhaust to reservoir 311.

It is during the indexing reciprocation of rack 250 that sequence valve 325 functions to prevent reciprocation of cylinder 193 and thus table 85. Such valve 325 is remotely controlled and such control isieiected when port 320 is open to port 16 343 and line 344. At that instant, pressurized iiuid is delivered by line 348 to valve 325, effecting thereby the closing of port 324 and stopping the ow of pressurized fluid in either direction with respect to chamber 264 of piston 193, thereby preventing reciprocation of said cylinder.

Provision is made in this fluid system for controlling the speed of reciprocation of cylinder 193 at all times by means of a flow control valve 333. Lever 353 on this valve may be used to set said valve to permit a denite pressure to build up in the system.- When this pressure is reached, port 35! of said valve is opened to port 352, and fluid under pressure is returned through lines 353, 353, 313, to reservoir 311.

Upon completion of the grinding operation, a grinding machine of my invention is automatically stopped. It was previously disclosed that a counting device counted the number of indexing reeiprocations made by rack 260. When all teeth of the workpiece have been indexed, this counting device closes an electric circuit energizing control solenoid valve 314. Such valve then opens port 3i3 to port 315 and the fluid under pressure from line 312 is delivered by line 354 to be returned to reservoir 311 by way of said valve and line 335, stopping the grinding operation until control lever 3l8 is used to again close port 313 to port 315.

It will be apparent from the foregoing description that the grinding machine of my invention as described and shown in the accompanying drawings has been described and illustrated in specific detail. It will be readily obvious that many modications, changes, or departures therefrom may be made without departing from the generic spirit and scope of the invention as set forth in the claims hereinafter set forth.

What is claimed is:

l. A grinding machine for grinding the anks of the teeth of gear-like machine elements comprising a base, a table mounted upon said base, means for moving said table in a rectilinear and substantially horizontal path upon said base, means for swinging said table about a substantially vertical axis with respect to the base, work holding means carried by said table including centering means defining an axis for rotatable support of a workpiece, which axis is generally parallel to the aforementioned rectilinear path, a grinding head independently supported by said base in a position above said centering means, means carried by said head for supporting a generally circular grinding wheel having a straight surface normal to its axis of rotation in al position wherein the wheel may overhang and contact a workpiece carried by said work holding means, and means for imparting lateral reciprocation to the work holding means in a path perpendicular to the aforementioned axis while simultaneously imparting oscillatory partial rotation to the centering means about such axis at a rate adapted to maintain rolling engagement between the aforementioned surface of the wheel and the flank of a too-th carried by a workpiece, including a work-oscillating motor entirely carried by and adapted to travel with said Work holding means and reacting against a fixed portion of the base to impart such transverse reciprocation to the work holding means, the means whereby the motor reacts against the base including an adjustable cam-type reaction element carried by the base whereby the length of the path ofre,

clprocating movement may be varied at will, and means responsive to such reciprocating move- 17 ment for imparting oscillatory partial rotation to the centering means, whereby by adjustment of said first-mentioned cam-type reaction member the length of the rectilinear reciprocatory movement and the extent of angular partial r0- tation may be simultaneously varied.

2. Means as set forth in claim 1 in which said means for imparting oscillatory rotation to the centering means includes adjustable reaction bands providing independent driving connection between the base and said work holding means.

3. Means as set forth in claim 1 in which said means for imparting oscillatory rotation to the centering means includes adjustablie reaction bands providing independent driving connection between the base and said Work holding means, and means for rotating the centering means independently of the bands for indexing, including a separate motor carried by the work holding means.

4. In combination with means as set forth in claim l, means including an actuating element carried by the base for reciprocating said table along said first-mentioned rectilinear path simultaneously with said oscillatory and reciprocating movement to feed such a workpiece longitudinally in a path parallel to the aforementioned surface of the wheel.

5. A grinding machine for grinding the anks of the teeth of gear-like machine elements comprising a base, a grinding head mounted thereon, said head including a generally circular grinding wheel having a flat surface normal to its axis of rotation and means for driving same, a work holder mounted on said base, said work holder including centering means and a work supporting element for rotatably supporting a workpiece, automatic fluid actuated means for reciprocating said work holder to move a workpiece mounted therein in a path normal to its axis of rotation, means to effect reciprocatory partial rotation of said work supporting element in accordance with said reciprocating movement, including a driving element carried by said base and a coacting driving element carried by the work holder, the combined rotational and reciprocating movements serving to cause the flank of a tooth of the workpiece to progressively contact the surface of the grinding Wheel along an involute path, common means for percisely limiting the magnitude of both of said reciprocatory movements, and means 18 including a vertical pivot operatively connecting the work holder to the base for swinging movement about a vertical axis.

6. A grinding machine for grinding the anks of the teeth of gear-like machine elements comprising a base, a grinding head mounted thereon, said head including a generally circular grinding wheel having a fiat surface normal to its axis of rotation and means for driving same, a work holder mounted on said base, said work holder including centering means and a work supporting element for rotatably supporting a workpiece, automatic uid actuated means for reciprocating said work holder to move a workpiece mounted therein in a path normal to its axis of rotation, means to effect reciprocatory partial rotation of said Work supporting element in accordance with said reciprocating movement, including a driving element carried by said base and a coacting driving element carried by the work holder, the combined rotational and reciprocating movements serving to cause the flank of a tooth of the 'workpiece to progressively contact the surface of the grinding wheel along an involute path, common means for precisely limiting the magnitude of both of said reciprocatory movements, means including a pair of tables, one supported by the other and both carried by the base, said tables being movable at right angles to one another upon the base and said Work holder being carried by said tables, and means including a vertical pivot also operatively connecting the work holder to the base for swinging movement about a vertical axis.

JAMES MARTIN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,870,764 Aeppli Aug, 9, 1932 2,207,018 Linse et al. July 9, 1940 2,262,103 Laessker Nov. 11, 1941 2,292,588 Terbrueggen Aug. 11, 1942 2,294,045 Orcutt Aug. 25, 1942 2,296,731 Mustonen Sept. 22, 1942' 2,387,166 Miller Oct, 16, 1945 2,387,167 Miller Oct. 16, 1945 

